The invention pertains to a (planar) polymeric optical waveguide device, such as an optical switch, splitter, phased array, Mach Zehnder interferometer (MZI), or the like, comprising at least one polymer waveguide channel embedded in a polymer cladding, said waveguide channel having a refractive index n.sub.2 higher than that of the cladding n.sub.1 and comprising at least one bend or curved section 10.
Bends are used to change the propagation direction of a mode or to reach a certain offset. For example, in optical 1.times.2 switches like those disclosed in G. F. Lipscomb et al., "Packaged thermo-optic polymer 1.times.2 switch," Conference on Optical Fiber Communication (OFC'95), San Diego, Technical Digest, Vol. 8 (Feb. 25, 1995), pp. 221-222, bends are needed to obtain a final output pitch or separation larger than 125 .mu.m between the two output channels required for the attachment of standard single mode glass fibres.
Unfortunately, small bend radii cannot be selected at will, because small radii (i.e., sharp bends) result in high loss through the conversion of guided modes into radiation modes. As a result, such optical waveguide devices cannot be made as compact as is often required (for technical or commercial reasons), especially when the devices comprise several bent waveguides and/or waveguides containing a plurality of bends (e.g., S-bends).